The present invention relates to the separation of minerals from ore, and, more particularly, to the separation of nahcolite from mined oil shale ore.
Large deposits of oil-bearing shale have been discovered in this country, but have remained relatively untapped for want of an economic process for recovery of the oil at a cost comparable to conventional oil sources. Some of these oil shale deposits also contain substantial quantities of other valuable minerals. Recovery of such minerals from oil shale deposits will help to make the recovery of the oil more economical.
One of the minerals found in substantial quantities in oil shale deposits is nahcolite, a naturally occurring sodium bicarbonate, which may be used as is or converted to sodium carbonate. If this nahcolite can be efficiently separated from the mined ore, prospects for profitable recovery of oil and other minerals from such deposits will be substantially enhanced.
Because of its limited availability, nahcolite has received little industrial interest. However, its effectiveness as a scrubbing agent for removal of oxides of sulfur, nitrogen, and other elements from flue gas and the like is expected to generate a substantial market when it can be made available in large quantities and at a low or moderate cost.
As used herein, the terms "ore" and "oil shale ore" refer to nahcolite-bearing oil shale, and "oil shale" refers to the residue which remains after the nahcolite has been removed from the ore.
"Nahcolite" is used herein to refer to the naturally occurring sodium bicarbonate. "Converted nahcolite" refers to nahcolite having at least a surface layer of sodium carbonate produced by heating the nahcolite. "Decomposed nahcolite" refers to nahcolite which has been substantially decomposed to sodium carbonate by heating, but which may have a nahcolite core.